//obj:运动对象，json：运动属性json格式，times：运动时间（不能大于间隔时间），fx：运动形式，fn：回掉函数

function startMove(obj, json, times, fx, fn) {
    var startTime = now();
    var iCur = {};
    for (var attr in json) {
        iCur[attr] = 0;
        if (attr == "opacity") {
            iCur[attr] = Math.round(getStyle(obj, attr) * 100);
        } else {

            iCur[attr] = parseInt(getStyle(obj, attr));
        }
    }
    clearInterval(obj.timer);
    obj.timer = setInterval(function () {
        var changeTime = now();
        var scale = 1 - Math.max(0, startTime - changeTime + times) / times;
        for (var attr in json) {
            var cvalue = parseInt(json[attr]) - iCur[attr];
            var value = Tween[fx](scale * times, iCur[attr], cvalue, times);
            if (attr == "opacity") {
                obj.style.filter = "alpha(opacity=" + value + ")";
                obj.style.opacity = value / 100;
            } else {
                obj.style[attr] = value + "px";
            }
        }
        if (scale == 1) {
            clearInterval(obj.timer);
            if (fn) {
                fn.call(obj);
            }
        }


    }, 13);

    //取得当前时间      
    function now() {
        return (new Date()).getTime();
    }
    //获得样式值     
    function getStyle(obj, sty) {
        if (obj.currentStyle) {
            return obj.currentStyle[sty];
        } else {
            return window.getComputedStyle(obj, false)[sty];
        }

    }

    //运动公式     
    var Tween = {
        //t : 当前时间   b : 初始值  c : 变化值   d : 总时间
        //return : 当前的位置 

        linear: function (t, b, c, d) {  //匀速
            return c * t / d + b;
        },
        easeIn: function (t, b, c, d) {  //加速曲线
            return c * (t /= d) * t + b;
        },
        easeOut: function (t, b, c, d) {  //减速曲线
            return -c * (t /= d) * (t - 2) + b;
        },
        easeBoth: function (t, b, c, d) {  //加速减速曲线
            if ((t /= d / 2) < 1) {
                return c / 2 * t * t + b;
            }
            return -c / 2 * ((--t) * (t - 2) - 1) + b;
        },
        easeInStrong: function (t, b, c, d) {  //加加速曲线
            return c * (t /= d) * t * t * t + b;
        },
        easeOutStrong: function (t, b, c, d) {  //减减速曲线
            return -c * ((t = t / d - 1) * t * t * t - 1) + b;
        },
        easeBothStrong: function (t, b, c, d) {  //加加速减减速曲线
            if ((t /= d / 2) < 1) {
                return c / 2 * t * t * t * t + b;
            }
            return -c / 2 * ((t -= 2) * t * t * t - 2) + b;
        },
        elasticIn: function (t, b, c, d, a, p) {  //正弦衰减曲线（弹动渐入）
            if (t === 0) {
                return b;
            }
            if ((t /= d) == 1) {
                return b + c;
            }
            if (!p) {
                p = d * 0.3;
            }
            if (!a || a < Math.abs(c)) {
                a = c;
                var s = p / 4;
            } else {
                var s = p / (2 * Math.PI) * Math.asin(c / a);
            }
            return -(a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p)) + b;
        },
        elasticOut: function (t, b, c, d, a, p) {    //正弦增强曲线（弹动渐出）
            if (t === 0) {
                return b;
            }
            if ((t /= d) == 1) {
                return b + c;
            }
            if (!p) {
                p = d * 0.3;
            }
            if (!a || a < Math.abs(c)) {
                a = c;
                var s = p / 4;
            } else {
                var s = p / (2 * Math.PI) * Math.asin(c / a);
            }
            return a * Math.pow(2, -10 * t) * Math.sin((t * d - s) * (2 * Math.PI) / p) + c + b;
        },
        elasticBoth: function (t, b, c, d, a, p) {
            if (t === 0) {
                return b;
            }
            if ((t /= d / 2) == 2) {
                return b + c;
            }
            if (!p) {
                p = d * (0.3 * 1.5);
            }
            if (!a || a < Math.abs(c)) {
                a = c;
                var s = p / 4;
            }
            else {
                var s = p / (2 * Math.PI) * Math.asin(c / a);
            }
            if (t < 1) {
                return - 0.5 * (a * Math.pow(2, 10 * (t -= 1)) *
                    Math.sin((t * d - s) * (2 * Math.PI) / p)) + b;
            }
            return a * Math.pow(2, -10 * (t -= 1)) *
                Math.sin((t * d - s) * (2 * Math.PI) / p) * 0.5 + c + b;
        },
        backIn: function (t, b, c, d, s) {     //回退加速（回退渐入）
            if (typeof s == 'undefined') {
                s = 1.70158;
            }
            return c * (t /= d) * t * ((s + 1) * t - s) + b;
        },
        backOut: function (t, b, c, d, s) {
            if (typeof s == 'undefined') {
                s = 3.70158;  //回缩的距离
            }
            return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
        },
        backBoth: function (t, b, c, d, s) {
            if (typeof s == 'undefined') {
                s = 1.70158;
            }
            if ((t /= d / 2) < 1) {
                return c / 2 * (t * t * (((s *= (1.525)) + 1) * t - s)) + b;
            }
            return c / 2 * ((t -= 2) * t * (((s *= (1.525)) + 1) * t + s) + 2) + b;
        },
        bounceIn: function (t, b, c, d) {    //弹球减振（弹球渐出）
            return c - Tween['bounceOut'](d - t, 0, c, d) + b;
        },
        bounceOut: function (t, b, c, d) {
            if ((t /= d) < (1 / 2.75)) {
                return c * (7.5625 * t * t) + b;
            } else if (t < (2 / 2.75)) {
                return c * (7.5625 * (t -= (1.5 / 2.75)) * t + 0.75) + b;
            } else if (t < (2.5 / 2.75)) {
                return c * (7.5625 * (t -= (2.25 / 2.75)) * t + 0.9375) + b;
            }
            return c * (7.5625 * (t -= (2.625 / 2.75)) * t + 0.984375) + b;
        },
        bounceBoth: function (t, b, c, d) {
            if (t < d / 2) {
                return Tween['bounceIn'](t * 2, 0, c, d) * 0.5 + b;
            }
            return Tween['bounceOut'](t * 2 - d, 0, c, d) * 0.5 + c * 0.5 + b;
        }
    }
}